The cache is not located at the posted coordinates. But feel free to go there as it is a popular place during summer time.
The cache is just hanging around at N 38 39.ABC W 121 09.DEF. You can restore order out of these chaotic numbers and do a little bit of arithmetic to obtain the final location.
1 2 5 6 5 6 2 1 1 2 6 5
ABC = 4 3 1 2 4 3 + 3 4 4 3 3 4
5 6 4 3 1 2 6 5 5 6 2 1
2 1 5 6 3 2 1 2
DEF = 6 5 1 2 2 1 - 3 4 4 3
3 4 4 3 4 1 5 6
Note: The attachment wire is pretty short, so please make sure it holds the cache tightly enough when replacing it.
You can validate your puzzle solution with certitude.
Congratulations to Dobbinsfam for FTF.